双向拉伸Hopkinson斜杆加载方法的探索与研究

Exploration and study on biaxial tensile Hopkinson oblique bar loading method

为了实现对材料的双轴同步拉伸加载,现已有通过双向电磁脉冲驱动,以及对称双曲杆产生的双向拉伸波的方式,对试样进行双向动态拉伸加载。试图探索一种结构简单,造价低廉,加工难度小的双向拉伸Hopkinson斜杆加载装置。为了理解斜杆对弹性压缩波传播规律的影响,对斜杆撞击进行了ABAQUS有限元仿真计算和理想验证试验分析。结果发现,斜杆夹角在低于60°和高于90°时,方波平台段出现前高后低的情形,导致波形失真,同时在夹角大于105°之后,失真更为严重。还对多轴加载的同步性问题和双轴加载的数据获取进行了讨论和分析。结果表明,加载波的不同步会导致试样上加载阶跃,从而加载应变率阶跃,这会影响率敏感材料的试验准确性。为了验证该装置的有效性,搭建验证装置对双向拉伸杆上的拉伸波形进行试验验证,取得了较好的试验结果。

In order to realize biaxial synchronous tensile loading of materials,biaxial dynamic tensile loading is conducted for specimens through the current existing mode of bidirectional electromagnetic pulse driving and symmetric hyperbolic bars generating biaxial tensile waves.Here,a biaxial tensile Hopkinson oblique bar loading device with simple structure,low cost,and small processing difficulty was explored.In order to understand effects of oblique bars on elastic compression wave propagation law,ABAQUS finite element simulation calculation and ideal verification test analysis were performed for impact of oblique bars.The results showed that when the angle between oblique bars is below 60°and above 90°,square wave platform segment has a situation of front high and rear low to cause waveform distortion,after the angle is larger than 105°,distortion is more severe.The synchronism problem of multi-axis loading and data acquisition of dual-axis loading were discussed and analyzed.The results showed that asynchronous loading waves can lead to step loading on specimens,and step loading strain rate to affect the test correctness of rate-sensitive materials.In order to verify the effectiveness of the explored device,a verification device was built to do test verification of tensile waveform on biaxial tensile bars,and better test results were obtained.